Paint billet grille black?
if you just paint it black, sand it and primer it so that the paint sticks well. i painted mine first and ended up with a bunch of tiny chips in it. my solution was a can of spray on bedliner coating. it has a little texture to it, but i can probably drag it down the road behind the car and it will still look good 
use some type of durable paint. maybe duplicolor wheel paint would be good since it's pretty tough if you just want to use paint. like i said above, i used the duplicolor truck bed coating and it came out great. regular paint will probably chip over time, but this stuff is hardcore so you won't have to worry about it again. it's not glossy, but kind of a matte finish with a texture to it, which looks great IMO.
this isn't a closeup, but it'll give you an idea.
this isn't a closeup, but it'll give you an idea.
